[settings] Add fetch_ipv6_setting()

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/core/settings.c

 	return fetch_ipv4_array_setting ( settings, setting, inp, 1 );
 }
 
+/**
+ * Fetch value of IPv6 address setting
+ *
+ * @v settings		Settings block, or NULL to search all blocks
+ * @v setting		Setting to fetch
+ * @v inp		IPv6 addresses to fill in
+ * @v count		Maximum number of IPv6 addresses
+ * @ret len		Length of setting, or negative error
+ */
+int fetch_ipv6_array_setting ( struct settings *settings,
+			       const struct setting *setting,
+			       struct in6_addr *inp, unsigned int count ) {
+	int len;
+
+	len = fetch_raw_setting ( settings, setting, inp,
+				  ( sizeof ( *inp ) * count ) );
+	if ( len < 0 )
+		return len;
+	if ( ( len % sizeof ( *inp ) ) != 0 )
+		return -ERANGE;
+	return len;
+}
+
+/**
+ * Fetch value of IPv6 address setting
+ *
+ * @v settings		Settings block, or NULL to search all blocks
+ * @v setting		Setting to fetch
+ * @v inp		IPv6 address to fill in
+ * @ret len		Length of setting, or negative error
+ */
+int fetch_ipv6_setting ( struct settings *settings,
+			 const struct setting *setting,
+			 struct in6_addr *inp ) {
+
+	return fetch_ipv6_array_setting ( settings, setting, inp, 1 );
+}
+
 /**
  * Extract numeric value of setting
  *

src/include/ipxe/settings.h

 
 struct settings;
 struct in_addr;
+struct in6_addr;
 union uuid;
 
 /** A setting */
 extern int fetch_ipv4_setting ( struct settings *settings,
 				const struct setting *setting,
 				struct in_addr *inp );
+extern int fetch_ipv6_array_setting ( struct settings *settings,
+				      const struct setting *setting,
+				      struct in6_addr *inp, unsigned int count);
+extern int fetch_ipv6_setting ( struct settings *settings,
+				const struct setting *setting,
+				struct in6_addr *inp );
 extern int fetch_int_setting ( struct settings *settings,
 			       const struct setting *setting, long *value );
 extern int fetch_uint_setting ( struct settings *settings,